Fluid pressure brake mechanism for railway oars



(No Modell) sheets-sheet 1.

y B. F. TBA'L. FLUID PRESSURE BRAKE MEOHANISM POR RAILWAY GARS.No.'5'36,106. `Patented Mar. 19, 189.5.

(Nd Model.) s sheetsheet 2.

B- 'Fl FLUID PRESSURE -BRAKE MEGHANISM POR RAILWAY GARS.

No. 536,106. y vPatented Mar. 19, 1895.

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8 Sheets-Sheet 3.

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B4?. TBAL. n FLUID PRESSURE BRAKE MEGHANISM FOR vRAILWAY GARS. No.536,106.

jule/r Patented Mar. 19, 1895.

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(No Model.) l

- PLUD PRESSURE BRAKE MGHANISM FOR RAILWAYCARS.v

Patented Mar. 19,1895.

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. B RTEAL FLUID PRESSURE BRAKE MBGHANISM.. FOR RAILWAY GARS. l

No. `536,106. Patented Mar., I19, 1895.

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1 YIM (No Model.) 8 Sheets-Sheet 6.

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FLUID' PRESSURE BRAKE MEGHANISMA POR'RAILWAY GARS. 1101536106.PatentedMar. 19, 1895.

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(No Model.) 8 'Sheets-Sheet 7.

B. I'. TBAL. PLUIE PRESSURE BRAKE MEEEARISM EUR RAILWAY GARS.

No. 536,106. Patented Mar. 19, 1895.

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(No Model.) 8 Sheets-Sheet 8. B.P. TEAL. A FLUID PRESSURE BRAKEMEGHANISM FOR RAILWAY GARS.

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wf//////////// a NITED STATES PATENT- FIIIcE.

BENJAMIN FnANKfTEAL, on oHIoAGo, ILLINOIS.

SPECIFICATION forming partof Letters Patent No. 536,106, dated March 19,i895. Application led September 1l., 1v894. Serial No. 522,719. (Nomodel.)

To all whom it may concern:

Be it known that I, BENJAMIN FRANKLIN TEAL, a citizen of the UnitedStates, residing at Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements inFluid-Pressure Brake Mechanism for Railway-Cars, of which I do declarethe following to be a full, clear, and exact description, referencebeing had to the accompanying drawings,forining apart of thisspecification. Y

My present invention, While applicable, so far as certain features areconcerned,to Huid pressure railway brakes of other kinds, has referencemore particularlyl to that class of railway bra-ke mechanism in whichboth the application and release of the brakes are effected by thepressure of air admitted to opposite ends of the brake cylinders.

One of the objects of my invention is to provide for Vmore effectivelyoperating the brakes by the admission of stored pressure to both ends ofthe brake cylinders.

Another object of my invention is to provide improved valve mechanismfor control ling the release of air from the brake cylinder.

A further object of invention is to provide improved Valve mechanism foreffecting the local reduction of train pipe pressure.

Another object of'invention is to provide means for automaticallystopping the train pipe exhaust when the proper point of train pipepressure reduction has been reached.

Astill further object of invention is to provide a governing valve thatWill serve t0 prevent the operation of the emergency or local exhaustcontrolling valve until the main piston has been operated.

Another object of invention is to provide an improved construction otengineer-s valve.

These several objects of invention I have accomplished by theimprovements hereinafter described, illustrated in the accompanyingdrawings, and particularly dened in the claims at the end ot thisspecification.

Figure lis a plan view showing the arrangement of brake cylinder,auxiliary reservoir, supplemental reservoir, actuating valve mechanismand trainpipe, with their suitable connections beneath the car. Fig. 2is a view 'similar to Fig. l, but showing a modified construction ofvalve mechanism and modified connections between the brake cylinder andthe auxiliary reservoir. longitudinal section upon an enlarged scale ofthe brake cylinderv and its piston. Fig. 4 is a plan view of the brakecylinder. Fig. 5 is a View in cross-section through the center of themain cylinder and the piston rod or trunk. Fig. 6 is aview in centralvertical longitudinal section through one form of my improved actuatingvalvemechanism. Fig. 7 is a view similar to Fig. 6, but showing theparts in different position. Fig. 8 is a view'in horizontal section online S 8 of Fig. b'. Fig. 9 is a view in vertical cross-section on line9-9 of Fig. 6. Fig. l0 is a plan view of the construction shown in Fig.6 with the cover of the casing removed. Fig. ll is a vertical centrallongitudinal section similar to Fig.,'outshow inga modified form ofemergency valve. Fig. l2 is a vertical cross-section on line l2-12ofFig. ll. Fig. 12a is a plan view of part of the casing shown in Fig. l2,adjacent tothe admission port for train pipe air. Fig. l2b is a view invertical section through the casing and cover shown in Fig. 12, thissection being taken on line 12b-l2 of Fig; 12a. Fig. 13 isa View similarto'Figs. 6 and 7, but showinga modified construction of admission pistonand valve. Fig. lat is a view similar to Fig. 13, but showing themodified form of emergency valve illustrated in Fig. 1l. Fig. l5 is aview similar to Fig. 14 with the parts in different position. Fig. 16 isa plan view with the cover removed, of the construction shown iuFig. 13.Fig. 17 is a view in horizontal section on line 17-17 of Fig. 13. Fig.18 is a view in vertical cross-section on line 18--18 of Fig. 13. Fig.19 is a detail plan View ofthe bottom cap. Fig. 20 is a view incross-section on line 20-20 ot' Fig. I8 looking up. Fig. 2l is a View invertical central section through my improved engineers valve mechanism.Fig. 22 is a detail view in vertical section on line :1c-:c of Fig. 2l.Fig. 23 is a detail view in vertical section on line y-y ofv Fig. 2l.Fig. 24 is a view in central vertical section through a modified form ofengineers valve.

Fig. 3 is a view in ICO Referring more particularly to Sheets 1 and 2 ofthe drawings, A designates the casing of my improved actuating valvemechanism.

2 is the train pipe.

3 is the brake cylinder.

L is the auxiliary reservoir.

5 is the supplemental reservoir and Gis the pipe leading from theauxiliary reservoir.

In the form of my invention illustrated in Figs. 6 to 12 of thedrawings, the actuating valve mechanism comprises a main casing A havinga cover A suitably connected thereto and when this form of my improvedvalve mechanism is employed, the casing A will be connected by a port awith the train pipe 2, by a port a2 with the end of the brake cylinder 3opposite the large area of the differential piston B within saidcylinder,and will be provided with a port a3 that connects with theauxiliary reservoir and with a port d4 through which air is admitted tothe supplemental reservoir 5.

In the preferred form of my invention the brake cylinder 3 has itspiston formed as shown more particularly in Fig. 3 ofthe drawings; thatis to say, with a hollow trunk b of suicient size to so obstruct orprotect one side of the piston B against air pressure as to give to thepiston thedesired differential operation, and one end of the brakecylinder 3 is provided with a port b that is suitably connected by apipe with a port a2 ol the valve casing while the opposite end of thebrake cylinder is provided with the port b2 which, inthe arrangementillustrated in Fig. 1 of the drawings, is in constant communication by abranch pipe with the pipe 6 that leads to the auxiliary reservoir 4.

The purpose in reducing the area of the brake cylinder piston B by meansof a stern or trunk b is to so reduce the surface of that side of thepiston that when an equal fluid pressure per square inch is delivered tothe oppositesides ot' the differential piston it will be caused to moveoutward by reason of the larger area exposed to pressure upon its innerside or end.

Air from the train pipe 2 is delivered by the port or passage a tothechamber 10 of the casingAa-nd from this chamber it passes bya port 11into the chamber 12 and lifting the check valve C it passes through theport controlled by this check valve into the chamber 13 and thence bythe passage c4 to the port a3 that connects with theauxiliary reservoirpipe 6. Train pipe air will also pass from the chamber 13 around thestationary check valve 16 that is carried by the fixed projection 14,into the chamber 17 (see Fig. 8), and from this chamber it will pass bythe port 15 into the chamber 19 formed in the upper part of the cap Aot' the main casing. The check valve 16 is shown as a cup leather valveand serves to prevent the bach dow of air into the chamber 13. Air issupplied to the supplementalreservoir from the chamber 17 in the cover Aby a channel am that leads from chamber 17 to the port a4 that connectswith the supplementalreservoir. (See Fig. 9.) lVithin the main casing Ais formed a channel 20 by which air delivered to the port d2 from theend ot' the brake cylinder opposite the large area of the piston isallowed to escape through the exhaust port 21 formed in the side wall ofthe casing. This channel 20 also serves for the admission of air to theend ot' the brake cylinder opposite the large area of the piston in amanner to be hereinafter defined. By preference there is formed adjacentthe exhaust port 21 a chamber 22, the bottom plate ot which is providedwith a port 23 that will be normally closed by the valve E at the end ofthe stem d3 ot' the main piston D, as seen in Fig. G ot the drawings.This main piston D has its upper side exposed to train pipe pressurewithin the chamber 1.0 ot' the main easing and the upper side et' thepiston D is preferably provided with arms (l adapted to contact with thecover A of the main casing in order to limit the upward movement of thepiston D. The lower side of the piston D is exposed to pressure ofstored air within the chamber 25, this air being admitted by the port a4from the supplemental reservoir 5 in order to maintain an approximatelyconstant and predetermined pressure within the chamber 25. To the mainpiston D is fixed a packing ring d held in place bya suitable nut andfollower and serving to form a tightjointabout the piston and around thestem cliof the main piston is fixed a packing ring 28 that serves toprevent the leakage around the piston-stem ot' air from the chamber 25.From the port a3 that connects with the auxiliary reservoir leads achannel al that connects by a point a8 with the channel 20 that leads tothe port a2 of the main casing. 'lhe port a8 is formed in the maincasing at a point above the admission valve G, the movements ot whichare controlled by the admission piston G, the upper surface of thispiston being exposed to train pipe pressure within the chamber 12 of themain casing.

From the construction as thus far defined it will be seen that the endof the main cylinder opposite the smaller area of the dilferentialpiston B is at all times in communication with the auxiliary reservoir4, while communication between the auxiliary reservoir f1 and theopposite end of the brake cylinder is controlled by means of theadmission valve G. When this valve G is in the position shown in Fig. 6,air can pass freely from the auxiliary reservoir through the port a3,channel a7, port a8, channel 20, and port a2 to the brake cylinder, butwhen the valve G is iu the closed position seen in Fig. 7, communication with the end of the brake cylinder opposite the large area ofthe differential piston and the auxiliary reservoir is eilt ott. Whenthe parts are in the position illustrated in Fig. 6 (termed the releaseposition), air from the auxiliary reservoir will be free to act upon IIO, larger area of the differential piston.

both sides of the differential piston B of the brakecylinder andinasmuch as the outer face of this piston presents a greater surface topressure of air, the piston B will be forced to a position opposite tothat shown in Fig. 3 of the drawings and this movement of the pistonwill effect the release of the brakes. Thenv it is desired to apply thebrakes for service application, the engineer will slightly reduce trainpipe pressure and under this slight reduction of pressure .the checkvalve C will close and thus prevent the back flow of air from theauxiliary reservoir, provided the closing of this check valve C has notalready taken place, although inasmuch as this check valve has likeareas exposed to fluid pressure on opposite sides, the valve will bereturned to closed position by gravity as soon as the pressure hasequalized within the auxiliary reservoir and train pipe. This exposureof both sides of the check valve C to like pressure is effected byforming the stem of the check valve with a groove c leading to thechamber c within which the stem of the valve is free to move. When trainpipe pressure is thus reduced in chambers 10 and 12 of the main casing,the admission piston G will be forced upward by reason of the pressurebeneath it and its valve G, of air from the auxiliary reservoir and theupward movement of this piston and its valve will cut off communicationbetween the auxiliary resorvoir and the end ofthe brake cylinderopposite the Thereduction of train pipe pressure within the chamber 10will allow the stored pressureA within the chamber 25 acting upon theunder surface of the main piston D, plus the pressure of air from thebrake cylinder acting upon the end of the piston-stem (Z3-that isexposed at the port 23, to raise the piston D thereby permitting theescape of air from the brake cylinder through the port a2, channel 20and ports 23 and 21 to the atmosphere. As soon as sufficient air hasbeen thus exhausted from the brake cylinder to materially lessen inpressure upon the end of the stem d3 of the main piston, the piston willmove downward and cause the Valve Eto close the exhaust, because underthe slight reduction of train pipe pressure above mentioned the store'dpressure within the chamber 25 at the under side of the main piston isnot sufficient of itself to retain the main piston in elevated position.The extent of brake action effected by this initial reduction of trainpipe pressure will be` proportionate to the difference in effectivepressure exerted by reservoir air upon the small area of thedifferential piston B and the resistance offered by lthe confined airupon the opposite side of the piston. It is obvious that the engineer inmaking service stops `0r in simplyslacking the speed of the. train canrepeat the slight reductions of train pipe' pressure until theresistance of air upon the large area of the brake piston is diminishedto the desired extent.

to the cover A and the mouth of this chanl nel or passage h. is adaptedto be normally closed by an emergency valve h', the stem h2 of which isconnected to the emergency valve piston H. Preferably the mouth of thechannel h is provided with a leather packing ring 40 to prevent theescape of air from the channel h to the chamber 4l from which exhaustports 42 open to the atmosphere. (See Fig. 9.) The stem h2 of theemergency valve 72, extends into the chamber19 anda packing ring 43 ispreferably provided around the stem 77,2 to guard against the leakage ofair from the chamber 19. The emergency piston I-I, preferablyconstructed as shown in Fig. 7 of the drawings, has its under sideexposed to stored pressure within the chamber 19, but the upper surfaceof this piston is exposed to train pipe pressure that is admitted by achannel 45 from the chamber 10 of the main casing. Stored pressure fromthe supplemental reservoir 5 is delivered into the chamber 17 by achannel am that connects this chamber with the port a4 to which thesupplemental reservoir is united, and from the chamber 17 storedpressure passes by the channel 15 into the 'chamber 19 beneath theemergency valve piston H. If desired the channel 45 may be provided witha governing valve 46 having a stem 47 that extends through the seat ofthe valve and into proximity to the main piston D. This governing valve46 will lift freely to permit the passage of airfrom the chamber 10 intothe channel 45 but will close automatically to prevent the back flow ofair from the channel 45 and will remain closed until the main'piston Dhas been lifted under the reduction of train pipe pressure. Consequentlythe emergency piston Isl (when this governing valve 46 is used), is notaffected by reason of train pipe pressure until the main piston D hasmade its initial movement and contacting with the stem 47 has lifted thegoverning valve 46 from its seat.

The main piston D and its stem d3 are preferably chambered as shown andwithin these chambers is held the exhaust stop valve piston K carryingthe exhaust stop valve 7c that serves to cut olf the exhaust of air fromthe train pipe when the desired reduction of train pipe pressure hasbeen attained. The piston K is preferably retained in place by ascrewcap 50 that is fixed at the top of the chamber of the main piston Dand through the opening in this cap 50 the upper surface of the piston Kis exposed to train pipe pressure within the chamber 1,0 of the casing.The lower side of the piston K is exposed to press- ICO ure acting inopposition to train pipe pressure and preferably this pressure consistsof stored air admitted to the chamber 52 of the main piston D beneaththe piston K through the ports 53 that communicate with the chamber 25which in turn receives stored pressure by port (t4 from the supplementalreservoir 5. The piston K is preferably provided with a packing ring anda packing ring is also pro vided at the lower end of the piston-stein inorder to guard against the leakage of air from the chamber 52. A ventport 54E leads from the bottom of the stem (Z3 into the chamber 22. rlhelower end of the channel t will be closed by the exhaust stop valve 7i:in manner to be presently defined, when the local exhaust of air fromthe train pipe is to be arrested.

From the foregoing description it will be seen that the operation of theform of 1ny invention above set forth is as follows: When the engineerdesires to apply the brakes for service stops, or for merely slackingthe speed of the train, he will, by means of his engineers valve eifecta slight reduction of pressure within the train pipe 2 and a corresponding reduction of pressure within the chambers 10 and 12 of the maincasing A. The effect of this slight reduction of train pipe pressurewill be that above set forth, namely, the cutting oif of communicationbetween the auxiliary reservoir and the end of the brake cylinderopposite the large area of the piston and the lifting of the main pistonD to effect the opening of the exhaust port 21 to permit the escape ofair from the end of the brake cylinder opposite the large area of thepiston. If however, it is desired to effect an emergency application ofthe brakes, the engineer will move his engineers valve to the emergencyposition so as to effect a sudden and greater reduction ot train pipepressure. Under this greater reduction of pressure within the chamber10, not only will the main piston D rise, thereby lifting the governingvalve etti from its seat and exposing the upper surface of the emergencypiston l-I to the reduction of train pipe pressure, but under suchsudden and greater reduction of train pipe pressure the pressure ofstored air within the chamber 19 upon the under side of the emcrgencypiston II will force this piston upward, thereby lifting the emergencyvalve 7L from the month of the exhaust ehannelor passage t and thuspermit train pipe air to escape from chamber 10, by the channel 7L andthrough the ports 4:2 to the atmosphere. It will be understood of coursethat up to this time the exhaust stop valve 7c and its piston K haveretained their normal positions with respect to the main piston D asshown in Fig. t5 of the drawings, because the area of the under side ofthe piston K. exposed to stored air pressure is so much smaller than thearea of the upper face of this piston and the valve 7c, which, at suchtime, are exposed to train pipe pressure. When however, a suilicientreduction of train pipe pressure within the chamber 10 has beeneffected, the stored air within the chamber 52 acting upon the underside of the piston K will force this piston upward thereby causing thevalve 7a to close the lower end of the channel 7L and thus arrestfurther exhaust of train pipe air. The parts will then occupy therelative positions seen in Fig. 7 of the drawings and the brakes will beapplied under emergency conditions. If now, it is desired to release thebrakes, train pipe pressure will be restored in the chambers l0 and 12of the main casing. The first effect of this restoration of the trainpipe pressure will be to cause the emergency piston 1I to descend andclose the upper end of the channel 7L; after which the exhaust stoppiston K will be forced downward by train pipe pressure, therebypartially withdrawing the exhaust stop valve 7n from the lower end ofthe channel 7L. The main piston D will then be re turned to normalposition, the exhaust stop valve r, being thereby completely withdrawnfrom the channel h. It will be seen that when the exhaust stop valve 7.ais in its normal position both the piston K and the valve are exposed totrain pipe pressure, but when the valve k is within the channel 7L thetotal effective area of the piston K exposed to train pipe pressure willbe by so much diminished. Consequently in order to restore the piston Kto its normal position, train pipe pressure must be raised to a pointconsiderablygreater than the point at which the piston K was allowed toclose the exhaust on the previous reduction of train pipe pressure. Thisfeature of providing for the closing of the emergency valve before theexhaust stop valve is returned to normal position is an important onebecause if the emergency valve were in open position at the time thatthe exhaust stop valve was returned to normal position, then a directrelease of train pipe pressure would occur at the Very moment when itwas desired to restore it, thus rendering it dillicult to restore trainpipe pressure. When the parts have been returned to the normal orrelease position shown in Fig. G, the airpassing from the auxiliaryreservoir through port a3, channel al, port as, channel 20 and port a2to the end of the brake cylinder opposite the larger area of thediiferential piston, will cause the release of the brakes in mannerabove set forth.

It will be understood of course that the scveral pistons of theactuating valve mechanism (with the exception of the admission pistonG), are differential pistons and that the areas of these pistons exposedto train pipe pressure and to stored pressure will be so relativelyproportioned as to insure the operation of the several pistons in themanner hereinbefore described. I have not deemed it necessary however,to define any precise areas for these pistons, as these will varyaccording to the size of the valve mechanism and according to ICO IIC

-valve mechanism.

Vsponding parts that thepoints ofjtrain 'pipe Areduction at which it maybe desired to cause the pistons andvalves to severally perform theirfunctions.

It will be seen that features of my invention Without its adoption' asan entirety. Thus,

for example, inFigs. 11, 12, 12, and 12? of the drawings, I have shown aslightly modi- ,fied construction of valve casing A and have shown a'modied construction of emergency In this form the valve casing A isprovided with a port 0.2 for connection with the end of the brakecylinder opposite'the larger area of the differential piston, and isprovided also with a port ai'v for connection with kthe auxiliaryreservoir and is provided with an admission piston G and valve Gidentical in construction and function with the valves before described.The same letters of reference are applied to Figs. 11, 12, 12 and 121kmindicateY correhave been hereinbefore described.,

The form of valve casing shown in Figs. 11,12,12ab and 12b has theadmission Aporta that connects with the train pipe formed on one side ofthe casing instead of at its end as in the construction alreadydescribed. From the chamber 13 above the check valve C, air passes by achannel 13Eb around the check valve 16 that consists of a cup leatherfixed to the lower end of the stem of the screw plug 16, and the airthus leaking around the valve 16 enters the chamber 17 and exertspressure upon the upper side of the'emergency valve' piston H4 that ismovahly sustained within the cylindrical opening a6 of the cover A sothat the under surface of this piston H4'is 'exposed to trainpipe-pressure within the chamber 1() of the main casing. In this form ofmy invention the emergency valve piston H4 is perforated and carries thetubular stem hs, the end of which constitutes an emergency valve hf thatsets over a projecting valveseat h2. The emergency valve r" comprises aleather packing ring that is attached to the end of the hollow sem hs bymeans ot' the rings hfand h5. (See Fig. 11.) The emergency valve himoves within a chamber 41a provided with exhaust ports 4t2, this chamberbeing preferably formed within a cap that is attached to the cover A ofthe casing by a threaded joint as shown. Preferably also a packing ring49 encircles the stem 71 of the emergency piston H4 so as to guardagainst leakage of air from the chamber 17.

By reference more particularly to Figs. 12 and 12", it will be seen thatthe chamber 17 is supplied with supplementary reservoir air passing tothis chamber by the channel am and by the port a4 that connects with thesupplemental reservoir. The construction of main piston D and of theexhaust stop valve 7c and its piston K is the same as that illustratedVin Figs. 6 and 7 and need not therefore be again. described, and in likemanner also air is delivered to the underside of the main piston fromthe supplemental reservoir 5 by a port leading to the chamber 25.

From the foregoing description it will be obvious that the operation ofthe valve mechanismsdescribed in Figs. 11 and 12 will be substantiallythe same as the operation of the mechanism illustrated in Figs. 6 and 7,

the only material point of difference being" that in the formillustrated in Fig. 11 the channel hs to which the local exhaust'oftrain pipe pressure is elfected is carried by the emergency valve pistonand the emergency valve has an annular valve that fits over a xed seat.When sufficientreduction of train pipe pressure has been effected by theengineer to cause the stored pressure Within the chamber 17 to depressthe 'piston H, the emergency valve hg will leave its plug-seat h2 andthus permit train pipe air to escape fromthe chamber lO of the maincasing; and reversely, when train pipe pressure has been restored to apoint at which it serves to overcome the stored pressure within thechamber 17, the piston H4 Will rise causing the emergency valve 719 toclose over this seat-plug h2. It will be understood however, thatin thisform of my invention as in that hereinbefore described, the areas of theseveral pistons Will be so proportioned that the emergency valve 'pistonH4 will cause the emergency valve to close before the exhaust stop valvelo has been withdrawn from the lower end of the exhaust channel 718. Ihave omitted from the construction shown in Figs. 11 and 12 thegoverning valve Ll'illustrated in Figs. 6 and 7, as this governing valveis not essential to the working of my invention in either of its forms.

In Fig. 13 of the drawings I have shown how the construction of the mainpiston and emergency valve mechanism and exhaust stop valve mechanismillustrated in Figs. 6 and 7 may be applied in connection with a type ofadmission piston and valve different from that shown in Figs. 6 and7,and in Figs. 16 to 2O of the drawings I have shown more particularlythe modifications of the main casing that are made when this type ofadmission piston and valve are employed and when the actuating valvemechanism is connected with the brake cylinder, the auxiliary reservoirand the train pipe in the manner illustrated in Fig. 2 of the drawings.The valve mechanism within the left-hand side of` the main `casing shownin Fig. 13 is the same (with the omission of the governing valve 46), asthe mechanism illustrated in Figs. 6 and 7 of the drawings, with theexception of slight differences in arrangement of the ports fordelivering air from the supplemental reservoir 5 as will be hereinaftermore particularly pointed out. So also the construction of valvemechanism at the left hand side of the casing in Figs. 14 and 15 of thedrawings, is the same I as that illustrated in Fig. 11 of the drawingsIOO IIO

` site the small area ofits differential piston to and the parts beingcorrespondingly lettered, l need not be again described in detail. Itwill be noticed however, thatin those forms of my invention in which atubular emergency valve piston is employed as in Figs. 11, 14: and 15,the admission port ot that leads to the chamber 10 of the main casing isshown as entering the casing from one side (see Fig. 12) instead of fromthe end as in Figs. 6, 'fand 13. I will now proceed to describe theconstruction and mode of operation of the admission valve G and itspiston G and the modifications of the casing and connections employedwith said type of valve and piston. I do not wish to be understoodhowever, as claiming in this application the specific construction ofthe admission valve and casing next to be described nor the arrangementby which the stored air is caused to be exhausted from one side of thebrake cylinder to the opposite side of the cylinder for the purpose ofreleasing the brakes, as this forms subject-matter of a separateapplication tiled by me of even date herewith, Serial No. 522,720.

In the following description it will be seen that the construction shownin Fig. 13 is the one illustrated fully in Figs. 1G to 20 of thedrawings, although the valve casing employed with this constructiondiders but very slightly from that employed with the construction ofvalve mechanism illustrated in Figs. 14 and 15. Referring therefore toFig. 13 and to Figs. 16 to 20 of the drawings, it will be seen that airfrom the chamber 13 at the upper righthand side of the main casingApasses bythe channel 13, around the check valve 16 into the chamber 17and thence passes by the channel and by channel Gl to a pipe leading tothe supplemental reservoir 5 and by this means the supplementalreservoir is supplied with compressed air from the auxiliary reservoir.Air from the supplemental reservoir passes through the lower part ofthechannel GO and by the branch channel 62 into the chamber 25 beneath themain piston D and by the branch channel 63 into a chamber 70 formedbeneath the under side of the admission pis ton G. This admission pistonG has its upper surface therefore exposed to train pipe pressure Withinthe chamber 12 of the main casing while its under side is exposed tostored pressure within the chamber working in opposition to said trainpipe pressure. Suitable packing rings 71 and 72 will be employed toguard against the leakage of air from the chamber 70, these packingrings being held in position as shown more particularly in Fig. 14; ofthe drawings. By preference the admission piston G is provided with astem g encircled by a sleeve g and at the lower end of this stem iscarried an admission valve G which serves to cut oithe admission ofstored air from lthe end of the brake cylinder oppothe channel 20 thatconnects with the end of ihe brake cylinder opposite the large area ofsaid piston.

By referring to Fig. 2 of the drawings it will be seen that with theform of casing illustrated in Figs. 13 to 2O of the drawings theauxiliary reservoir 4 connects by a pipe (l with a port a' at the backof the valve casing (see Figs. 1G and 1S) and into this port a air isdelivered by the channel 8O (see Figs. 1T and 1S) from the chamber 13above the check valve C. From the port a' auxiliary reservoir air passesdownward through the lower part ot the channel 8O and then around in thedirection of the arrow, Fig. 19, into the space 8l beneath the deliveryvalve G2 (see Fig. 14) whereby the delivery of air from the auxiliaryreservoir to the brake cylinder is controlled. The air passing upwardfrom the space 8l beneath the valve G2 and through the port 83 (see Fig.13) that is closed by said valve passes through the port Si and thencepasses by the port as to the end of the brake cylinder opposite thcsmallarea of the differential piston, it being understood of course thatair thus passes to said end of the cylinder only when it is desired toetfect the application of the brakes. When the parts are in the positionillustrated in Figs. 13 and 14 of the drawings, which is the normal orrelease position, there is a free communication between the end ol' thebrake cylinder opposite the small area ot' the piston and the oppositeend of this cylinder by way ofthe ports a3, Set, as, channel 2O and porta2, and by reason of the greater area exposed to pressure by the outerend of the differential piston, the piston will be held in a positionopposite that shown in Fig. 3 of the drawings to retain the brakes fromoff the wheels. lf now it is desired to apply the brakes for the purposeof making service stops or for merely slacking the speed of the trainthe engineer, by means of the engineer-s valve, will make a slightreduction of train pipe pressure in manner hereinbefore described. UnderthisV reduction of train pipe pressure the admission piston G' willrise, lifting the admission valve G until it passes the port 84: andthus cuts off communication between the opposite ends of the brakecylinder. The main piston D will also rise under the reduction of trainpipe pressure within the chamber 10 thereby lifting the valve E from itsseat and permitting an exhaast of air from the end ot' the brakecylinder opposite the larger area of the differential piston throughport 0.2, channel 20, chamber 22 and port 21 to the atmosphere. As theadmission piston G continues to rise, the delivery valve G2 will passfrom out the port 83 thereby permitting auxiliary reservoir air to passfrom channel 8O (see Figs. 18 and 1U) by space 81 and ports S3, 8l anda3 to the end ol' the brake cylinder opposite the small area of thepistou. (See Fig. 2.) The pressure of auxiliary reservoir air thusdelivered to the small area of the dilferential piston, within the brakecylinder while the opposite end of the brake cylinder is incommunication with the atmosphere as above deiined, will cause thediier- IOG ential piston to move to the :position shown in Fig. 3 of thedrawings, thereby electing the application 'ot' thebrakes. emergencyapplication of the brakes is desired, a greater reduction ot' train pipepressure will be made bythe enginee1"svalve,and the exhaust stop valve,in both the constructions shown by Figs. 13 and 14 will be brought intooperation in the manner hereinbefore explained. bo also it is obviousthat when it is desired to release the brakes, train pipe pressure willbe restored and the main piston D, the emergency valve H and the exhapststop valve will be returned to normal position as hereinbefore describedand on such increase of train pipe pressure the admission piston GWillbecaused to descend to the position seen in Fig. 13 of the drawings,thereby first closing communication between the auxiliary reservoir andthe brake cylinder and again opening communication through the valvecasing between the opposite ends ofthe brake cylinder. As soon ascommunication is thus established between the opposite ends of the brakecyiinder, confined air passing from the end of the brake cylinderopposite the smaller area ot the differential piston will enter thebrake cylinder opposite the larger area of the piston and by reason ofthedifference in areas thus exposed to like pressure the dilerentialpiston will be moved to a position the reverse of that shown in Fig. 3of the drawings and will thus effect the release of the brakes.

The engineers valve illustrated in Figs. 21, 22 and 23 of the drawingscomprises a casing T that is suitably connected by a channel t to thetrain pipe 2 and by a channel t to a pipe 90 that leads to the usualmain reservoir on the locomotive or tender. The casingT is also providedwith a port or channel t2 that communicates with an exhaust pipe 91openingto the atmosphere. The channel t admits air from the mainreservoir to the cylinder t3 and from this cylinder main reservoir airwill pass by an opening t4 into the chamber t5. This chamber i?communicates by a port t6 with the chamber wherein is held the plugcockU that is operated by the usual handle or lever within reach of theengineer as well understood. The plug-cock U is a three-way cock, beingprovided with ports u., u and u2. Vhen this cock U is in the positionseen in Fig. 2l of the drawings, main reservoir air will pass from thechamber i5 by port t and by the port u and uof the cock U into a channel'u formed within the vcasing T andV adapted to be closed by a cut-offvalve V which, when in closed position, tits within the packing ring 94that constitutes a seat for the valve. The valve V is carried by apiston V preferably furnished at its top with a packing ring fu', thispiston being movably held within a cylinder t7 at the top of the casingT. A coil spring 95 bears upon the under face of the piston V and servesto hold this piston in raised position when the pressure \Vhen theV ofair upon its opposite sides is equalized. Air from the main reservoirwill be admitted to the chamber 96 above the piston V by a channel 97that communicates with the chamber 98 to which main reservoir air isadmitted from the chamber i5 by a port 99, this port being normallyclosed by a check/valve W that is furnished with a cup leather to insureits tightly closing the port. The chamber wherein the plug-cock U isheld communicates bya port t8 with the channel t that leads to the trainpipe 2 and communicates byaport i9 with a chamber im that connects withthe exhaust port 152.

From the description as thus far given it will be seen that when theparts are inthe position shown in Fig. 21 of the drawings, air from themain reservoir will pass by the port i', cylinder t3, opening t4,chamber i5, port 6, ports u and u of the plug U, channel c, and chamberuw to the channel t that leads to the train pipe 2, and pressure of mainreservoir air will thus be maintained within the train pipe; and thisposition ofthe engineers valve is what is commonly termed the runningposition. It will be seen also that with the parts in thisposition, mainreservoir air will pass from the chamber t5 into the chamber 98 andthence by channel 97 to the chamber 96 above the cut-off piston V.inasmuch as both sides of the piston V are thus exposed to equal airpressure, the coil spring 95 will maintain the piston V and the Valve Vat such time in raised position, thus allowing the air to continue topass from the main reservoir to the train pipe. It from any causehowever, a break or leakage inthe train pipo or its couplings, or a useof the conductors `valve should occur while the plug-valve U is in therunning position shown, the sudden decrease ofA pressure within thetrain pipe will effect a corresponding reduction of pressure beneath thepiston V thereby allowing the excess air pressure upon'the upper side ofthis piston to force the piston downward so as to cause the valve V toclose the channel c and thus prevent further admission of air from themain reservoir into the train pipe. Loss of air from the main reservoirWill thus be automatically prevented in case 0f any escape of air fromthe train pipe other than thatcaused by the proper setting of theengineers valve.

When the engineer desires to effect a reduction of pressure withinthetrain pipe for the purpose of making service stops or for merelyreducing the speedot' the train, he will turn the lever of theplug-valve U to the position indicated by the dotted lines oppositewhich the words Service-stop are written, thereby bringing the port upartially coincident' with the vport t8, and the port u2 partiallyopposite the port t9 thus allowing a gradual escape of air {.rom thetrain pipe through the channel t, the above mentioned ports and the portor channel t2, at the same time cutting off the main reservoir byclosing IIO port t. From the port t2 the air will escape to theatmosphere through a cylinder X wherein is movably mounted an annularValve X that closes over a fixed seat or plug X2 comprising preferably acup leather held upon the lower end of a sleeve o; by means ot athreaded bolt or stem that passes through a fixed bracket or spider m2within the casing X. rl`he annular valve X has its outer peripheryprovided with a piston X3, the upper end of which is exposed to pressureot air escaping from the train pipe while its lower side is exposed toair within the annular chamberor space x4 between the casing X and thetubular stem and the exhaust stop valve X. Preferably a cup leatherpacking ring is provided as shown at the under side ot' the piston X3 and a similar packing ring encircles the stem :t5 of the exhaust stopvalve at the base ot' the chamber From the chamber @c4 a pipe 100 leadsto a port 101 that communicates with the casi ng of the plug-Valve 102(see Fig. 22), from the casingot which valve achannel 103 leads to thespace above the stem w of the check valve W. The stem w of this checkvalve is provided with a channel wthat connects the chamber 98 with thespace above the stem w and consequently when the valve 102 is in theposition shown in Fig. 22, main reservoir air from the chamber 0S willpass through the pipe 100 to the chamber as beneath the piston X301? theexhaust stop valve X. The pistou X3 of the exhaust stop valve is adifferential piston as the upper end ot' this piston exposes a largerarea to air pressure than does that partot the piston exposed within thechamber :rt llence while the pressure of stored air within the chamber:r4 tends to hold the piston X3 and the valve X' inthe position shown,it is obvious that when the engineers valve has been turned so as toadmit train pipe pressure to the upper face of the piston, the latterwill be forced downward and away from the fixed seat or plug X2 thusallowing the air to escape from the train pipe until the pressure ot'such air is so far reduced that it is insullicient to retain the pistouX3 in depressed position and will consequently allow the stored airwithin the chamber m4 to raise the valve X thereby causing it to stopthe further exhaust of air t'roin the train pipe. Hence it will be seenthat when air is allowed to escape from the train pipe by turning thecock of the engineer-s valve in manner above indicated this escape ofair from the train pipe will continue until the desired degree ofreduction is attained, when the valve X will be lifted by the stored airwithin the chamber El and will arrest further exhaust 0l trainV pipeair, the limit of such reduction being determined by the reductionnecessary to give the full emergency application of the brake mechanism.It may be sometimes desirable to reduce the pressure within the chamber08, or within the chamber t4 beneath the exhaust stop pistou X3. Bymeans of the valve 102 an escape of air can be had from either of thesechambers, as will be obvious by reference to Fig. 22 of the drawings; orit' for any reason it is desired to throw the exhaust stop valveout ofservice, the valve 102 can be turned so as to blank the ports 100 and103 and thus cut of the passage ol' air between the chamber 0S and thechamber beneath the exhaust stop piston. The valve casing will beprovided with suitable ports 110 and 111 to which will be connected theusual dual pressure gage for indicatingtothe engineer thcpressureswithin the main reservoir and train pipe respectively.

In order to permit a considerably greater pressure to be maintained inthe main reservoir than is used in the train pipe I prefer to employtheconstruction of pressure reducing valve next to be described. This valvecomL prises two pistons Y and Y carried by the stem y] and workingwithin the cylinder t3 of the lnain casing. The periphery ot' each ofthese pistons is preferably provided with cup leathers in order tosecure a tight joint. The piston Y serves as a valve to regulate thepassage of air from the main reservoir through the opening t". To thepiston valve Y is connected a supplemental piston Y2, the stem {1/2 otwhich extends within a chamber yfsuitably attached to the main casing,the outer end of this chamber being preferably closed by a threaded capp4. The stem y2 of the supplemental valve Y2 is encircled by a coilspring Y3, one end of which bears against the end of the chamber g3while its opposite end bears against the head of the stem if. Thechamber g3 connects with the chamber L5 by means ot the channel g4 sothat the chamber ff has therein at all times the same degree ofairpressure as the chamber 5. The areas of the pistons Y and Y being thesame, the pressure of main reservoir air within the cylinder t3 willhave uo effect upon these pistons, they beingin equilibrium. Thesupplemental piston Yzhowever, is exposed to the air pressure within thechamber y and the area of this supplemental piston is such that it willexert a tendency to force the piston valve Y to close the port t4. Thecoil spring Y acts in opposition to the supplemental piston Y2 and theforce of this spring is so adjusted as to equal the opposing force ofthe supplemental piston Y2 under the degree of pressure desired to benormally carried in the train pipe. It will therefore be seen that whenthe pressure within the chamber t5 exceeds the desired normal pressure acorresponding excess of pressure will be exerted in the chamber g3 andupon the supplemental piston Y2 thereby overcoming the resistance of thespring Y3 and causing the Valve piston Y to partially or entirely closethe port t* that leads to the main reservoir pipe. On the other hand, as

soon as the pressure falls within the chamber t5 the spring Y3 willagain move the Valve piston Y outward so as to open the port 't4 topermit the free passage of air from the main res- IOC ervoir pipe. Itwill thus be seen that any desired pressure can be maintained in thetrain pipe regardless of any higher pressure within the main reservoir;and it will be seen also that by carrying avery high-pressure within themain reservoir the capacity of this reservoir is proportionatelyincreased without a corresponding increase in size.

In view of the well recognized mechanical equivalency ot flexiblediaphragms for pis.

1 struction of engineers valve in which a fiexible diaphragm is employedto perform the function of the valve operating piston V shown in Fig. 2lof the drawings. Referring to this modified construction, t designatesthe pipe leading from the main reservoir and 2 denotes the'train pipethat communicates by the channel t with the main casing T of the valve.Within the upper part of the main casing T is placed the diaphragm V(ito which is connected a valve V7 that closes a port orchannel o4 of thecasing. In this moditied form of the invention the stem of the valve V7is tubular and by means of this stem air can pass from the chamber abovethe valve seat v4 through the ports Q12 and o3 to the chamber beneaththe flexible diaphragm V6 and thence into the channel t that leads tothe train pipe 2. From the main reservoir pipe 90 a passage 97 leads tothe chamber 96 of the casing above the diaphragm V6 and within the lowerpart of the casing is placed a th reeway plug-cock U corresponding tothe cock shown in Fig. 21 of the drawings and operated by the usualengineer-s hand lever 115. The chamber wherein the plug-cock U iscontained communicates with the main reservoir pipe 90 by a passage tand by a passage 1580 communication is had between this chamber and thechannel t that leads to the train pipe. Anl

`the diaphragm. If however, from any cause pressure is reduced in thetrain pipe while the parts are in the normal or running position shown,a corresponding reduction of f pressure uponthelunder side of thediaphragm It will thusr will allow the excess pressure upon the upperside of the diaphragm to force this diaphragm and the valve V7 downwardthereby causing tbe valve to close against its seat and cut off furthercommunication between the main reservoir and the train pipe. In thepassage 97 that leads from the main reservoir pipe to the space 96 abovethe diaphragm V6 is interposed a check valve W4 that will serve toprevent the back` flow of air from the chamber above the diaphragm whenany reduction of pressure occurs in the main reservoir, thus maintaininga constant pressure within the chamber 96 above the diaphragm to insurethe prompt closure of the valve V7. InV this last form of the inventionI have not deemed it necessary to illustrate either the exhaust stopvalve or the pressure reducing valve.

Certain features of the valve mechanismv herein shown and described butnot claimed form the subject-matter of a separate application, SerialNo. 522,720, tiled by me September l1, 1894, and I do not wish to beunderstood as claiming herein such features as are hereI shown anddescribed but specifically claimed in said companion application.

WVhat I claim as new, and desire to secure by Letters Patent, is

l. In an automatic tluid pressure brake system, the combination of abrake cylinder, an auxiliary reservoircounected with and supplying theair used in both ends ot' said cylinder, whereby both the applicationand release of the brakes are effected by stored pressure, a train pipe,and an actuating valve mechanism, said actuating valve mechanism beingprovided with an exhaust port, whereby ai-r is allowed to escapefromsaid brake cylinder and being provided also with independ ent admissionand escape valves and pistons for controlling the admission and escapeof air to and from said brake cylinder and with an independent passageuncontrolled bysaid pistons whereby air is supplied from the train pipeto the auxiliary reservoir, substantially as described.

2. In an automatic fluid pressure brake system the combination ofabr-alie cylinder, an auxiliary reservoir connected with and supplyingthe air i used in both ends of said cylinder,V whereby both theapplication and release of the vbrakes are effected by stored pressure,atrain pipe, and an actuating-valve mechanism suitably connected withsaid train pipe, said reservoir and said brake cylinder; said actuatingvalve mechanism being provided with an exhaust port by which air is a1-lowed to escape from the release end of said brake cylinder and beingprovided also with suitable valvular appliances for effecting thesimultaneous exposure oi both sides ot' the piston within the brakecylinder to stored pressure when the brakes are to be released andwithan independent passage uncontrolled by said pistons whereby air issupplied from the train pipe to the auxiliary reservoir, substantiallyas described.

IOO

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3. In an automatic iiuid pressure brake system the combination with abrake cylinder having a differential piston therein, an auxiliaryreservoir supplying the air used in both ends of said cylinder wherebyboth the application and release of the brakes are effected by storedpressure, a train pipe, and an actuating valve mechanism suitablyconnected with the train pipe, with the brake cylinder' and with theauxiliary reservoir, said actuating valve mechanism being provided withan exhaust port by which air is released from the end of the brakecylinder opposite the larger area of its piston, a valve for controllingsaid exhaust port, a piston exposed to train pipe pressure for operatingsaid valve, an independent valve for controlling the admission of storedpressure to said end of the brake cylinder opposite the larger area ofthe differential piston an independent piston exposed to train pipepressure for operating said controlling valve and an independentvalve-controlled passage connecting the train pipe andthe auxiiiaryreservoir, substantially as described.

4. In an automatic fluid pressure brake system, the combination with abrake cylinder' having a dierential piston therein, an auxiliaryreservoir supplying the air used in both ends of said cylinder, wherebyboth the application and release of the brakes are ef fected by storedpressure, a train pipe and an actuating Valve mechanism suitablyconnected with said train pipe, said reservoirand said brake cylinder;said actuating valve mechanism being provided with an exhaust port bywhich air is released from the end of the brake cylinder opposite thelarger area of the piston, a valve for controlling said exhaust port, apistou for operating said valve exposed on one side to train pipepressure and upon its opposite side to a substantially constant pressureof stored air within a chamber independent of reductions of pressure inthe train pipe and auxiliary reservoir, an independent valve forcontrolling the admission of stored duid pressure to the end of thebrake cylinder opposite the larger area of the piston and an independentpiston for operating said independent valve exposed on one side to trainpipe pressure and upon its opposite side to a pressure in opposition tosaid train pipe pressure, substantially as described.

5. ln an automatic iiuid pressure brake system, the combination with abrake cylinder having a differential piston therein, an auxiliaryreservoir supplying the air used in both ends of said brake cylinderwhereby both the application and release of the brakes are effected by astored pressure, a train pipe, and an actuating valve mechanism suitablyconnected with said train pipe, said reservoir and said brake cylinder;said actuating valve mechanism being provided with an exhaust port bywhich air is released from the end of the brake cylinder opposite thelarger area of the piston, a valve for controlling said exhaust port, adilerential piston for operating said valve exposed on one side to trainpipe pressure and upon its opposite side to a substantially constantstored air pressure within a chamber closed against back flow of airtherefrom to both the train pipe andthe auxiliary reservoir and actingin opposition to said train pipe pressure,an independent valve forcontrolling the admission of stored pressure to the end of the brakecylinder opposite the larger area of the piston and an independentpiston for operating said independent valve exposed on one side to trainpipe pressure and upon its opposite side to a pressure in opposition tosaid train pipe pressure, substantially as described.

6. In an automatic du id pressure brake system, the combination of atrain pipe, a brake cylinder having a differential piston therein, anauxiliary reservoir in constant communication with the end of saidcylinder opposite the small area of its piston and connected by a valvedpassage with the opposite end of said brake cylinder, an exhaust portfor the escape of air from the end of said brake cylinder opposite thelarge area of its piston and suitable valve mechanism exposed to trainpipe pressure for controlling the admission and exhaust of air to andfrom said end ofthe brake cylinder opposite the large area of its pistonand provided with an independent valve controlled passage connecting thetrain pipe and auxiliary reservoir, substantially as described.

7. In an automatic tiuid pressure brake system, the combination of atrain pipe,a brake cylinder having adiferential piston therein,anauxiliary reservoir in constant communication with the end of saidcylinder opposite the small area of its piston and connected by a valvedpassage with the opposite end ot' said brake cylinder, and an actuatingvalve mechanism having an exhaust port for the escape of air from theend of said brake cylinder opposite the large area ot' its piston, avalve for controlling said exhaust port, a piston for actuating saidvalve exposed to train pipe pressure on one side and upon its oppositeside to a substantially constant pressure of stored air within achamberat all times independent of reductions of pressure in both the trainpipe and auxiliary reservoir, an independent valve for controlling theadmission of air to the end of said brake cylinder opposite the largearea of its piston, and a piston exposed to train pipe pressure foractuating said independent valve, substantially as described.

8. In an automatic iiuid pressure brake system, the combination of atrain pipe, a brake cylinder having a differential piston therein, anauxiliary reservoir in constant communication with the end of saidcylinder opposite the small area of its piston and connected by a valvedpassage with the opposite end oi said brake cylinder, and an actuatingvalve mechanism comprising a casing having an ex- IOO IIO

haust port therein for the escape of air from the end of the brakecylinder opposite the large area of its piston, a valve Within saidcasing for controlling said exhaust port, a piston for operating saidvalve, an independentvalve Within said casing for controlling theadmission of air to the end of said brake cylinder opposite the largearea of its piston, an independent piston for loperating saidindependent valve, and suitable chambers Within said casing for exposingsaid valve-operating pistons on one side to train pipe pressure and upontheir opposite side to a pressure in opposition to said train pipepressure and with a valve controlled passage independent of said pistonwhereby the admission of air from the train pipe to the reservoir iseffected, substantially as described.

9. In an automatic iinid pressure brakesystem, the combination with abrake cylinder, aA train pipe, and an auxiliary reservoir, of anactuating valve mechanism comprising a casing having an exhaust port forventing air from the brake cylinder and a main piston for controllingsaid brake cylinder exhaust, said main piston being exposed on one sideonly to train pipe pressure and on its opposite side to pressure Withina chamber permanently separated from said train pipe pressure by saidpiston, and closed against access thereto of air from the brake cylinder.and a Valve fixed at the end of said piston stem and exposed to the airpressure of that end of the brake cylinder to which said exhaust port isconnected, whereby the reductionof pressure Within said end of the brakecylinder tothe required degree will permit said valve to close andarrest the exhaust from said cylinder,

substantially as described.

10. In an automatic iluid pressure brake system, the combination with abrake cylinder, a train pipe, an auxiliary reservoir and suitableconnections, of a casing provided with an exhaust port or passage, avalve and main piston for controlling said exhaust port or passage, achamber within said casing connected with the train pipe and wherein oneside of said main piston is exposed to train pipe pressure, a passageleading from said chamber to locally exhaust the train pipe, anemergency valve normally closing said local exhaust passage, and anindependent piston exposed in said chamber to train pipe pressure on oneside only for controlling said localexhaustpassage,`said piston beingexposed upon its opposite side to stored pressure Within a chamberindependent of both the train pipe and the auxiliary reservoir underreductions of pressure in said train pipe and auxiliary reservoir,substantially as described.

1l. In an automatic duid pressure brake system, the combination with abrake cylinder, a train pipe and an auxiliary reservoir, of Valvemechanism having exhaust passages for venting air from the train pipeand brake cylinder, a main piston exposed to train pipe pressure and avalve for controlling said brakel cylinder exhaust, an emergency valveLand piston for controlling said train pipe exhaust, said emergencyvalve piston being exposed to train pipe pressure on one side only, andbeing exposed on its opposite side to stored air pressure Within achamber independent of both the train pipe and auxiliary reservoir underreductions of pressure in said train pipe and auxiliary reservoir, and asupplemental governing valve serving to prevent the local exhaust oftrain pipe air until the main piston has made its initial movement,substantially as described.

12. In an automatic fluid pressure brake system, the combination With abrake cylinder, a train pipe, and an auxiliary reservoir, of anactuating valve mechanism comprising a casing having exhaust passagesfor venting air from the train pipe and from the brake cylinder, a mainpiston and valve for controlling said brake cylinder exhaust, separatevalve mechanism for controlling said train pipe exhaust and an exhauststop valve and its piston exposed to and arranged to be shifted by areduction of train pipe pressure Yto cut ott the exhaust from the trainpipe when the train pipe pressure has been reduced to the requiredextent, substantially as described.

13. In an automatic iuid pressure brake system, the combination of acasing having an exhaust port or passage for venting air from the trainpipe, valve mechanism controlling the escape of air through said port orpassage, an exhaust stop valve for checking the flow of air through saidport or passage, and a piston for causing said exhaust stop valve toclose said passage, said piston being 'exposed on one side to trainpipe' pressure and arranged to be shifted by a reduction of said trainpipe pressure and being exposed upon its other sideto a pressure inopposition to train pipe pressure, substantially as described.

llt. In an automatic luid pressure brake system, the combination of acasing having an exhaust port or passage for venting air from the trainpipe, an emergency valve for normally closing said exhaust port orpassage, a piston for opening said exhaust port or passage, said pistonbeing exposed on one side to train pipe pressure and upon its oppositeside to pressure independent ofthe train pipe reductions, an exhauststop valve for closing said port or passage and a piston for bringingsaid stop valve into action, said piston being exposed on one side totrain pipe pressure and arranged to be shifted by a reduction of saidtrain pipe pressure and being exposed upon its other side to a pressureindependent of trainpipe pressure, substantially as described.

15. In an automatic fluid pressure brake system, the combination of acasing having an exhaust port or passage for venting air from the trainpipe, an emergency valve for normally closing said exhaust port orpassage, a piston for opening said exhaust port or pas- IOO IIC

sage, an exhaust stop valve for closing said port or passage and apiston for bringing said stop valve into action,the said pistonsexposing relatively different areas to train pipe pressure and topressure in opposition thereto, whereby the shiftof said emergency valvepiston is effected bya considerably less red notion of train pipepressure than is required to effect the shift ot said stop valve piston,substantially as described.

1G. In an automatic iluid pressure brake system, the combination of acasing having an exhaust port through which air is vented from the trainpipe, a channel leading to said exhaust port, a valve for closing oneend of said channel against passage oi' train pipe air therethrough, apistou for opening said channel and exposed to train pipe pressure, anexhaust stop valve for closing the opposite end of said channel, and apiston for causing said exhaust stop valve to close said channel, saidpistou being exposed to and arranged to be shifted by a reduction oftrain pipe pressure, substantially as described.

17. In an automatic fluid pressure brake system, the combination with acasing having suitable admission and exhaust ports or passages thereinand having a main piston and valve for controlling the brake cylinderexhaust, of an emergency valve and piston for normally closing the portfor escape of air from the train pipe, andan exhaust lstop valve andpiston for closing said escape port for train pipe air when thepredetermined limit of emergency reduction of train pipe pressure hasbeen reached, said stop valve and its piston being carried by said mainpiston, substantially as described.

18. In an automatic fiuid pressure brake system, the combination of acasing having an exhaust port through which air is vented from the trainpipe, a channel leading to said exhaust port, a valve for closing oneend of said channel against passage of train pipe air therethrough, apiston for opening said channel and exposed to train pipe pressure, andan exhaust stop valve and its piston for closing the opposite end ofsaid channel, both said exhaust stop valve and piston being exposed totrain pipe pressure when the adjacent end of said channel is open, andsaid exhaust stop valve being protected from train pipe pressure whenseated to close said channel, substantially as described.

19. In an air brake system, an engineers valve mechanism comprising acasing having an exhaust port or passage for venting air from thetrainpipe, valve mechanism controlling the escape of train pipe air throughsaid port or passage, an exhaust stop valve for checking the iow of airthrough said port or passage, and a piston for causing said exhaust stopvalve to close said passage, said piston being exposed on one side totrain pipe pressure admitted through said controlling valve mechanismand upon its opposite side to pressurein opposition to said train pipepressure, substantially as described.

20. In an air brake system, an engiueers valve mechanism comprising acasing having an exhaust port or passage for venting air from the trainpipe, valve mechanism controlling the escape of air through said port orpassage, an exhaust stop valve for checking the How of air through saidport or passage, a piston for causing said exhaust stop valve to closesaid passage, said piston being exposed on one side to train pipepressure, an air chamber connected with the main reservoir, a checkvalve to prevent the back iiow of air 'from said chamber and a pipe orchannel connecting said chamber with a space at the side of said pistonnot exposed to train pipe pressure, substantially as described.

2l. In an air brake system, an engineer-s valve mechanism comprising acasing having an exhaust port or passage for venting air from the trainpipe, valve mechanism controlling the escape of air through said port orpassage, an exhaust stop Valve for checking the fiow of air through saidport or passage, a piston for causing said exhaust stop valve to closesaid passage, said piston being exposed on one side to train pipepressure admitted thereto by said controlling valve mechanism and a pipeor channel for admitting substantially uniform stored pressure to theopposite side of said piston, whereby the pist0n will be shifted whenthe desired train pipe reduction is effected, substantially asdescribed.

22. In an air brake system, the combination With a main reservoir pipeand with a train pipe, of an interposed valve mechanism having a passagesuitably connecting said pipes, a piston fitting snugly Within acylinder of said valve mechanism, a valve operated by said piston andserving to control the passage of fluid between said pipes, one side ofsaid piston being exposed to train pipe pressure and the other side ofsaid piston being exposed to a substantially constant pressureindependent of reductions in the main reservoir pressure and acting inopposition to said train pipe pressure, whereby when the pressure uponopposite sides of said piston is equa-l said controlling valve willremain open, but When the pressure within the train pipe decreases, thesubstantially constant pressure acting upon the opposite side of saidpiston will cause said valve to automatically close, substantially asdescribed.

23. In an air brake system, the combination with a main reservoir pipeand With a train pipe, of an interposed valve mechanism having a passagesuitably connecting said pipes, a piston fitting snugly within acylinder of said valve mechanism, a valve connected to said piston andserving to control the passage of fluid between said pipes, one side ofsaid piston being normally exposed to stored fluid pressure Within achamber connected to a pipe IIO

